Charging system (CS) alternators are used in large numbers of vehicles and have numerical designations denoting the outside diameter in millimeters of the stator coil. For example, a CS-144 alternator has a stator outside diameter of about 144 millimeters. This CS number can be used to compare relative size and amperes output of different alternators. The CS-144 type alternator, for example, is typically a large case alternator that fits many large or heavy duty General Motors vehicles and Hummers. The CS-144 alternator can come in different output levels, for example, 190 amps and 210 amps. This alternator usually includes rotor windings forming a rotor coil and mounted on a rotor shaft, a stator coil, double sealed ball bearings, contoured rotor segments, an internal fan, long life brushes, high temperature insulation, and a high capacity and rugged bridge rectifier mounted adjacent a rear cover of the alternator body. A fan is mounted next to a pulley in the front section of the alternator and draws air through rear air vents in a rear cover and through front air vents for cooling the alternator components. An internal fan is typically mounted on a rotor shaft and also draws air through a slip ring and frame assembly to aid in cooling the rectifier bridge, any regulator device positioned in the alternator body and the rear bearing. The air is expelled through air vents at the “pulley” or front end.
Many of these types of alternators use a high capacity and rugged bridge rectifier having positive and negative heat sinks that are spaced adjacent to each other and forming a gap therebetween. Button diodes are soldered on respective sides of the heat sink facing each other. Insulating spaces having terminals of a terminal assembly and/or lead frame are positioned between the positive and negative heat sinks and interconnect the button diodes to complete the rectifier circuit.
Although the CS-144 alternators and their bridge rectifiers as described usually form a robust alternator, the button diodes sometimes fail when a shear force such as created by excessive vehicle or other vibration, is applied to any solder joint securing the button diodes to the sides of the heat sink. Even without any added shear force applied to a solder joint, the joint could fail because of excess heat.
Some prior bridge rectifiers for CS-144 and similar alternators have used press fitted diodes in their designs, but the configuration of the cooling fins on the heat sinks, the location of the press fitted diodes relative to the overall configuration of the heat sinks, or the generally small configuration of the cooling fins have not been advantageous. Overheating has sometimes occurred because of inadequate heat sink cooling.